Surroundings-sensor-based EBA (Emergency Brake Assist) systems or collision mitigation systems (CMS) are known. These systems are based on sensors covering the surroundings, which sensors are usually radar sensors mounted on the vehicle front. The systems cover the region in front of the vehicle and are capable of assessing the risk of collisions with vehicles driving ahead or objects lying ahead.
These systems aim at assisting the driver in critical situations (risk of rear-end collisions) when the driver has to perform an emergency braking maneuver, wherein the assistance consists in, e.g., prefilling the brake system or lowering the tripping limits for the hydraulic braking assistant. Recently developed systems automatically initiate vehicle braking, even without involving the driver where appropriate. Depending on the respective design, the duration and/or intensity and/or gradient of said braking are/is limited or unlimited.
Furthermore, FCW (Forward Collision Warning) systems are known, which warn the driver when there is a risk of collisions with vehicles driving ahead or objects lying ahead. Objects are detected by means of sensors covering the surroundings, such as radar sensors and/or camera systems. The driver is warned visually, acoustically and/or haptically, e.g., by a brief automatic build-up of brake pressure.
Emergency steering systems are a further development of forward collision warning systems and emergency braking systems. They are not commercially available yet, but are described in research and in numerous patent specifications.
For example, emergency steering systems can adapt vehicle behavior situationally and thus adapt it to a possible emergency steering situation, e.g., by rear-axle steering and stabilizer bars. Furthermore, emergency steering systems can warn the driver, e.g., visually, acoustically or haptically.
Furthermore, steering interventions and/or braking interventions can assist the driver during the emergency steering maneuver in order to perform a safe lane change. Furthermore, an automatic evasive maneuver can be performed by the system.
Usually, but not necessarily, an emergency steering system requires the effected activation of an emergency braking system. Especially with high relative velocities and with low coefficients of friction, an evasive maneuver is mostly still possible much later than a braking maneuver in order to avoid a collision. Since a braking maneuver is usually performed in one's own lane but is often safer than steering on account of the reduction of kinetic energy (steering resulting in lane departure results in being endangered by oncoming traffic, for example), the effected activation of an emergency braking system is a useful activation condition for an emergency steering system.
In particular, the occurrence of false positive errors when the system is not used must be avoided in order to ensure the operatability of the system according to, e.g., ISO 26262.
The operatability of forward collision warning systems and emergency braking systems is usually ensured by means of continuous runs, in which the data of the surroundings-covering systems (e.g., radar data) and data of the ego-vehicle (CAN data) are recorded. Thus, by a software-based simulation of the signal processing chain, false positive errors can be detected and statistically analyzed. In this way, the robustness of systems the activation of which is based on the positive piece of sensor information “Object Detected” can be ensured. Such systems are, e.g., forward collision warning systems and emergency braking systems. For example, the detection of an object that does not really exist is a false positive error. For example, such misinterpretations may occur when radar systems detect bridges. Therefore, with above-mentioned functions, a false-positive-error activation of a function can be mostly put down to a false positive error of the system that covers the surroundings. The opposite is the case when a free zone is detected for an emergency steer assistant, where the non-existence of objects in the zone into which the vehicle can move when performing an evasive maneuver must be reliably detected. Therefore, a surroundings-covering system that avoids false negative errors is required for ensuring the operatability of an emergency steer assistant.